Appendix :
Proofs of all statements in the manuscript.
Appendix :
Relation between our secrecy conditions and Coecke's “non-signalling from terminality” argument in modular theories [1]}.
Appendix :
Relaxing some of the assumptions of the present approach.
Appendix :
Additional minor results on commuting agents and minimal constructions.
Appendix :
Application to generalized probability theories.
Appendix :
Generalizing the derivation of secret agents to extended secrecy in the presence of global functions, and to the case where the two monoids of transformations do not commute.

